A convention commonly used over preempts is the Leaping Michaels convention. It is a conventional overcall made in defense to an opposing 2-level or 3-level preempt. Leaping Michaels is played by many pairs as it provides a means to show very strong game forcing two-suited hands (5-5 or longer) that are less suitable than using a takeout double.

Leaping Michaels, utilizes the 4 and 4 bids. Similar to the Michaels cuebid, in case this minor suit overcall is in the opposing suit, both major suits are implied. In case the overcall is not a cuebid, the suit bid plus a major suit is indicated. So, on preempts of the opponents (indicated between brackets), the following applies when playing Leaping Michaels:
(2/3) – 4: Clubs and spades
(2/3) – 4: Diamonds and spades
(2/3) – 4: Clubs and hearts
(2/3) – 4: Diamonds and hearts
(3) – 4: Majors
(3) – 4: Diamonds and an undisclosed major
(3) – 4: Clubs and an undisclosed major
(3) – 4: Majors
After 3 or 4, the bid of 4 asks for a major. The bids 4 and 4 are to play. Following 3 or 4, the bid of 4 is played as passor-correct.
Some partnerships prefer to interchange the meanings of the 4 and 4 bids following a 3 preempt so that 4 denotes diamonds and an undisclosed major. This has the advantage that the 4 becomes available to ask for the major suit. The 4/4 responses may then be played as natural (to play). Discuss this with your partner!
Leaping Michaels can be utilized after natural two-level preempts and also after conventional preempts such as the Muiderberg convention, also called the Dutch Two opening. It is a preemptive opening based on a two-suiter with precisely a five-card major and a minor suit (four-cards or longer). In Muiderberg the 2 opening denotes five hearts and an unknown minor suit, while 2 denotes five spades and an unknown minor suit. It can also be played over the Multi 2 diamonds preempt which shows a weak two bid in either major. Here Leaping Michaels can be utilized to good effect:
(2) – 4: Clubs and an undisclosed major (4 asks for the major)
(2) – 4: Diamonds and an undisclosed major (4is pass-or-correct).

If you currently play 2/1 using Michael cuebids, you may want to consider add the Leaping Michaels Convention.